Summary A Fokker 28 was holding on runway 06 while a Beechcraft 1900 was taxiing on the same runway. In addition, a Dash 8 was on final for runway 06. Because the Beechcraft was slow to exit the runway, the controller trainee asked the Fokker to exit the runway to allow the Dash 8 to land. The Beechcraft exited the runway while the Dash 8 was on short final. The controller trainee cleared the Dash 8 for landing when the Fokker was not yet off the runway. The pilot-in-command of the Dash 8 saw the navigation lights of the Fokker and executed a missed approach. Ce rapport est galement disponible en franais. Factual Information It was dark, and Quebec City Airport, Quebec, was under the influence of a low-pressure system with ceilings at 200 feet and visibility of 2,600 feet in fog. Runway 06 was in use and aircraft were executing ILS approaches. Traffic was light. Only a Beechcraft 1900 - Bizex 954 and a Dash 8 - AAQ125 were on approach. A Fokker 28 - ICN 1668 was holding for departure. Due to poor visibility, runway 06 was not visible from the control tower. The controllers had two radar screens providing RAMP (Radar Modernization Project) information, which clearly showed the aircraft on approach for runway 06. There was no ground radar. Five controllers were on duty at the time of the occurrence: at airport control, there were one controller-instructor, one controller trainee, one ground controller, one co-ordinator, who was not in the tower when the incident occurred, and one operations support specialist. There was no supervisor. After the Beechcraft landed, the crew of the Fokker lined up their aircraft on the runway; at that time, the Dash 8 was on final and seven nautical miles (nm) out. The crew of the Beechcraft was not familiar with the airport, and they were taxiing slowly towards taxiway Alpha. While the Beechcraft was still taxiing on the runway and the Dash 8 was at 3 nm, the controller trainee asked the crew of the Fokker to exit the runway via taxiway Golf. As another aircraft was there already, the Fokker headed for taxiway Hotel, located 1,600 feet from the threshold of runway 06. This manoeuvre was confirmed by the controller trainee. The three controllers were closely following the Beechcraft's progress. When the Dash 8 was at 1 nm, the Beechcraft confirmed that it had exited onto taxiway Alpha. The controller trainee cleared the Dash 8 to land when it was 1/2 nm out and the Fokker was approaching taxiway Hotel. On crossing the runway threshold at 100 feet above ground level (agl), the pilot-in-command of the Dash 8 saw the navigation lights of the Fokker, which was still on the runway. He immediately executed a missed approach and flew over the Fokker, which at that time was at the usual touchdown point for an ILS approach. The controller trainee had 24 years' experience as a terminal controller. He had recently started training as an airport controller. His progress was normal. The controller-instructor had known the controller trainee for several years and considered him very competent. Air traffic control takes place in a complex environment involving time constraints, multiple tasks, and teamwork. It involves the processing of information presented simultaneously via visual and auditory means. Controllers not only must know their jobs but also must be able to solve problems effectively. They have to adapt workload management strategies for taking action within critical timeframes. Air traffic control requires that information be visualized and manipulated in two dimensions, but processed in three dimensions. Controllers must rapidly and correctly interpret the changing information received from radar screens, flight progress strips, and communications with flight crews and other controllers. They act on that information while complying with regulations and established procedures and safely expediting air traffic.